What to establish before buying a used centrifuge, and how to read the rest of the market beside it: why used centrifuges and a used centrifuge for sale or used centrifuges for sale listing are priced on the rotor and the service history rather than the drive, what a refurbished centrifuge should have had done to it, what a centrifuge price or a laboratory centrifuge price actually covers, how a centrifuge cost is built up over ten years of rotors and service visits, and what to confirm before ordering from a centrifuge for sale listing, a centrifuges for sale page, a centrifuge machine for sale advertisement or a centrifuge machine price quotation

What to establish before agreeing a price

1. Which rotors are included, and what life is left. A rotor has a rated number of runs or years at full speed, and a responsible seller keeps a log. Ask for the rotor part numbers, their age, the log if one exists and the maker's derating or retirement policy. A machine with no rotor, or with a rotor at the end of its life, is a drive with a large purchase still attached.
2. The service history and who did it. Ask when it was last serviced, by whom, what was replaced and whether the maker will still support the model. Support status decides the instrument's remaining life more than its age does, and a discontinued model without parts is worth what its rotors are worth.
3. What a refurbishment included. Refurbished means different things to different sellers. The useful questions are whether the drive bearings were replaced, whether the lid interlock and imbalance detection were tested, whether the refrigeration was serviced and whether the instrument was run at full speed with a loaded rotor afterwards. Ask for that test to be recorded.
4. Safety systems, tested rather than assumed. The lid interlock, the imbalance cut-out and the rotor identification are the systems that stand between a failure and an injury. They are also the systems nobody checks on a machine that appears to work. Require evidence that each was tested, and re-test them at installation.
5. The cost that arrives afterwards. Count the rotors you will need, the adaptors for your vessels, a service contract or the cost of a visit, and the replacement of any consumable vessel. On a ten-year view these regularly exceed the purchase price, and a comparison that omits them is comparing the wrong number.

What ages, and what does not

Drives and cabinets last a long time and are repairable. Refrigeration ages on the compressor and the seals. Electronics and displays age on a technology cycle and are the usual reason a working machine cannot be repaired. Rotors age on a documented schedule that is not negotiable.

So the right questions are about the rotor log, the refrigeration service and the availability of control boards, in that order. A twenty-year-old mechanically simple instrument with a good rotor and a serviceable drive is frequently a better buy than a ten-year-old one with an obsolete controller.

Buying from a dealer, a laboratory or an auction

A dealer who refurbishes and warrants gives a tested instrument and a route back if it fails, at a price that reflects that. A closing laboratory sells an instrument that was working last month with no warranty and often no rotor log. An auction sells an instrument nobody has switched on.

Each can be the right choice, and the discount should match the risk being accepted. What should never vary is the requirement to test the safety systems and to establish the rotor's history before the machine is used, whoever it came from.

Transport, installation and the first run

These instruments are heavy, and floor-standing ones need equipment to move and a floor that will take them. Transport with the rotor removed and separately packed, and expect the instrument to need levelling and a balance check on arrival.

Run it empty, then with a balanced load at moderate speed, then at the speed you intend to use, listening and watching each time before it is trusted with a sample. Record the result: that first run is the baseline any future vibration or noise complaint is judged against.

Common questions

Is a used centrifuge a safe purchase?

It can be an excellent one, provided the rotor's age and run history are known, the safety interlocks are tested and the maker still supports the model. The rotor carries the risk and most of the value, so a machine sold without rotor records is an unknown.

What should a refurbishment have included?

Drive bearings checked or replaced, lid interlock and imbalance detection tested, refrigeration serviced where fitted, and a full-speed run with a loaded rotor afterwards, recorded. Ask for that record rather than the word.

Does the quoted price include a rotor?

Often not, and that is the largest single variable. Ask which rotors are included by part number, what life is left on each, and what the adaptors for your own vessels cost, then compare.

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